Morphological changes of Golgi apparatus in adult rats after facial nerve injuries.

We examined the morphological changes of Golgi apparatus (GA) of the facial motor neurons in rats after facial nerve avulsion or axotomy. In rats after avulsion, the numbers of motor neurons showed reduction and fragmentation of GA, namely the organelle lost the normal network-like configuration which was replaced by numerous small disconnected elements (fine fragmentation). This GA fragmentation was morphologically indistinguishable from that previously reported in amyotrophic lateral sclerosis (ALS). On the other hand, axotomy did not induce significant motor neuron loss, and the GA had lost the elongated profiles (coarse fragmentation). These results suggest that there may be a similar cascade leading to motor neuron death in rats after avulsion, and ALS and GA observed in rats after axotomy may not be related to neuronal death.